Boiler tube coating attempts to provide reasonable protection of the furnace tube from damaging surface effects. In this article, we will learn about the most effective current coating methods and how VIVABLAST performs boiler tube repair & coating for clients.
Boiler tube coating: The ultimate and sustainable protection for your boiler tubes
In order to fully convey the information to you, this article will go through the following contents:1. What is boiler tube coating, and why is it necessary?2. Top 4 boiler tube coating methods
- Thermal Spray Coating on Boiler Tube
- Tungsten carbide coating
- High-Velocity Oxygen Fuel Coating
- Arc Spray System method
3. Introducing coating solutions provided by VIVABLAST
1. What is boiler tube coating, and why is it a must to all the constructions using boiler tubes?
Boiler tube coating is a method of forming a corrosion protective coating on the outside of the furnace tube by altering the material’s surface properties. When the furnace tube is coated with anti-corrosion coating, its surface will possess corrosion resistance properties from the spray coating components.
The coating will help protect boiler tubes from problems related to corrosion, wear, chemical attack, slag, thermal wear, or hysteresis. Above is all the damage that boiler pipes face when placed in harsh environments, plus high working capacity for a long time.Moreover, when properly coated, tubes can increase their durability and extend their service life, helping to reduce maintenance, repair, or replacement costs. Less damaged boiler tubes also help limit losses due to system downtime for maintenance and repair.
Read more: Boiler Tube Coating by HVOF – The popular and effective protection method
2. The best boiler tube coating & repair technologies: From thermal spray to arc wire spray
When it comes to boiler tube coating, there are four most widely-applied methods, including:
- Thermal Spray Coating on Boiler Tube
- Tungsten carbide cobalt coating
- High-Velocity Oxygen Fuel Coating
- Boiler Tube Coating By Arc Spray System
1. Thermal spray coating
Thermal spray coating (metal coating/metalization) converts a solid material in powder form, wire, rod, or drug core into a stream of high-energy material such as a combustible gas or a plasma stream, thereby melting the material. The material, after melting, will disperse in the form of a fine mist and be pushed to the surface to be coated at high speed, forming a protective coating.Coating the boiler tube by thermal spray method is popular thanks to the following outstanding advantages:
- Do not consume too much material
- Create a coating of just the right thickness, meeting all needs, from creating new surfaces to restoring old ones.
- Be applied to sophisticated and complex structures
- Increase the heat resistance, wear resistance, and corrosion resistance of metals, thereby increasing their service life
- Increase electrical conductivity
2. Tungsten carbide cobalt coating
The HVOF tungsten carbide thermal injection process creates extreme kinetic energy into the powder particles. When these energetic particles collide with the substrate, their velocities turn to zero, and they absorb kinetic energy, causing them to bond with the embryo immediately. After that, a coating is quickly formed. Thanks to this unique operating principle, the tungsten carbide coating has an exceptional thickness and good adhesion.The main advantages of this coating technology are:
- High bond strength
- Low residual stress
- Low porosity (usually less than 0.5%)
- High resistance to wear and corrosion
3. High-Velocity Oxygen Fuel Coating
High-velocity oxygen fuel (HVOF) coating, invented in the 1980s, is the term for the process of mixing liquid fuel and oxygen, which is then injected into the combustion chamber and ignited. The gas mixture carries high temperature and pressure and is sprayed at supersonic speed, and hot air and powder are directed towards the coated surface. The finish coating is a thick, low-porous, and highly bonding coating.Some advantages that make HVOF an effective boiler tube coating method:
- Higher density
- Lower oxide content
- The chemical powder is retained
- Smooth coating surface
- High hardness
- Low residual stress => high thickness
4. Arc Spray System
Arc wire spraying (double arc/thermal arc spraying) is a method of using an electric arc to melt a conductor. The arc spray system works on the “push” or “push/pull” principle.
- The “push” system that pushes the wire into the gun is lighter and easier to use than the “push/pull,” which is generally applied to hardwire materials and machine-to-gun distances.
- The “push/pull” system is used in cases where the distance from the machine to the gun is long or where soft wire materials such as zinc and aluminum are used. The “push/pull” system pulls the two leads to the gun, causing them to squeeze together, forming an electric arc and melting the wire. Compressed air passing through a nozzle atomizes the molten metal and sprays it onto the workpiece.
Some advantages of boiler tube coating by arc wire system:
- Cost savings
- Applicable to many surface materials such as Metal, Wood, Polystyrene, Plastic, Glass, Paper, and Ceramics
- Nice aesthetics
- Low heat input level, suitable for heat-sensitive substrates. It also helps limit the risk of heat distortion.
3. What is the boiler tube repair & coating method that has been widely provided by VIVABLAST?
One of the four coating methods mentioned above, VIVABLAST’s strength lies in the thermal spray technique’s first method. Our service portfolio covers metal coating/plating such as Thermal Spray Aluminum (TSA) / Zinc (TSZ) / other metal alloys. Our coating solutions can serve many different industries, including boiler tube coating. Why does VIVABLAST choose to offer clients with the thermal spray coating? Because this is considered a simple solution, optimal in terms of time and cost, this method is also compatible with many different substrate materials.
Our thermal spray service will be an ideal choice for the following types of surfaces:
- The surface requires high precision, no thermal deformation, and no residual stress
- The surface of non-metallic material with high hardness
- The coated surface with a layer of metal with an increased thickness such as electroplating
Read more: Thermal spray coating service delivered by VIVABLAST
What clients can get when they trust and choose to work on the boiler tube repair & coating project with VIVABLAST:
- Appropriate solution based on actual assessment;
- The process is methodically designed and meets international standards;
- A team of qualified and experienced technicians;
- Reasonable cost and construction time
Before concluding this article, we hope to provide you with practical and valuable information about the importance of boiler tube coating and the most efficient coating methods. If you are looking for a company that specializes in offering boiler tube protection solutions with optimal quality and cost, please don’t hesitate to get in touch with VIVABLAST via:
- Phone: (+ 84-28) 38 965 006/7/8
- Fax: (+ 84-28) 38 965 004
- Email: vivablast@vivablast.com
